Field of the Invention
The present invention relates to a shower apparatus that discharges aerated bubbly water.
Description of Related Art
A shower apparatus which discharges bubbly water by aerating water using a so-called ejector effect is known. Such shower apparatus can reduce the amount of water usage via aeration. Meanwhile, such shower apparatus also reduces a stimulus sensation felt by a user when discharged bubbly water hits skin of the user, and this has been presented a problem in that a comfort feeling of the user of the shower apparatus is impaired.
In view of the above, the applicant has proposed the shower apparatus described in JP2012-187346 A. The shower apparatus described in JP2012-187346 A periodically varies the amount of air mixed into the water, whereby pulsation is provided to bubbly water to be discharged. Such pulsation is felt by the user of such shower apparatus as a stimulus sensation. As a result, a stimulus sensation reduced by aerating water to be discharged can be supplemented by such pulsation.
Further, the shower apparatus described in JP2012-187346 A periodically changes the direction of a main water stream ejected toward an aeration unit from a throttle unit comprised inside the shower apparatus, by the effect of a swirl formed in the vicinity of such main water stream, whereby the above-mentioned pulsation is provided to bubbly water to be discharged. More specifically, the direction of ejection of water from the throttle unit, the shape of a channel wall surface, etc., are devised such that a state in which the direction of a main water stream has been changed due to a negative pressure produced inside a swirl and a state in which the direction of a main water stream has returned due to a swirl reduced in size (in turn, a reduced negative pressure) are repeated in a self-induced and periodic manner. In this way, only a simple configuration allows bubbly water to be provided with self-induced pulsation, without separately providing a complicated mechanism, such as a pump for periodically varying the pressure of the shower stream.
However, in a shower apparatus having the configuration described in JP2012-187346 A, the phase and period of pulsation provided to bubbly water may differ depending on the position of a nozzle hole, resulting in unstable pulsation.
The possible reason for this problem is as set forth below. Regarding water that has been ejected radially from a throttle unit toward an outer circumference of the shower apparatus, most of such water is discharged to the outside as shower-like bubbly water; meanwhile, part of such water flows back toward a throttle unit through an inner space. Such backflow water is received in a swirl chamber and becomes a cause that generates a swirl in the vicinity of a main water stream. That is, the size of a swirl (size of a negative pressure) that varies the direction of a main water stream is affected by the flow rate of the backflow water.
If backflow water that flows from the direction of the outer circumference toward the inner circumference (i.e., backflow water that flows from all directions to the swirl chamber) has a uniform flow-rate distribution, the size of the swirl, and thus, the size of the negative pressure produced inside such swirl is also uniform in all directions, and the direction of the main water stream will therefore vary entirely with the same period and the same phase. As a result, uniform (same phase and same period) pulsation is provided to the entire bubbly water to be discharged, leading to the stable continuation of such pulsation.
However, for example, water streams ejected from the throttle unit toward different directions may interfere with each other, or some water streams may collide with inner wall surfaces of the shower apparatus, resulting in a non-uniform distribution of the flow rate of the backflow water that returns from the direction of the outer circumference to the swirl chamber. In such case, the size of a swirl that changes the direction of a main water stream, and the time when such swirl occurs, etc., will differ depending on the location, and the phase and period of pulsation provided to bubbly water are also not uniform in the entire shower apparatus (such phase and period will differ depending on the position of a nozzle hole). Pulsations with different phases may temporarily offset each other, and this causes unstable pulsation as a whole.